The Federal Aviation Administration has opened an investigation into whether airports in San Antonio, Texas, and Buffalo, New York, discriminated against Chick-fil-A when they denied the fast-food chain vending space, the U.S. Transportation Department said Friday.

“The Department has received complaints alleging discrimination by two airport operators against a private company due to the expression of the owner’s religious beliefs,” the federal said in a statement. “FAA’s Office of Civil Rights has notified the San Antonio International Airport (SAT) and Buffalo Niagara International Airport (BUF) that it has opened investigations into these complaints.

"The FAA notes that Federal requirements prohibit airport operators from excluding persons on the basis of religious creed from participating in airport activities that receive or benefit from FAA grant funding," the statement continued. "The findings of the investigations will be communicated to the complainants once the investigations are completed.”

The cities cited the chain's sometimes vocal opposition to same-sex marriage as a factor in denying airport vending space.

The move by the FAA is in line with recent legislation in Texas that seeks to prevent government entities in the state from taking "adverse action" against people and businesses based on their affiliations with religious organizations as defined by federal tax laws.

The measure gained traction in the Legislature when organizations such as Texas Values began a lobbying effort aimed at preventing actions that would allow local governments to use a business' religious associations when awarding public contracts.

The conservative First Liberty Institute, based near Dallas, was quick to pounce on the announcement that the FAA would examined circumstances surrounding the decisions to deny airport space to Chick-fil-A.

“We are pleased that the FAA responded to our request by opening an investigation into San Antonio for its blatant, illegal religious discrimination against Chick-fil-A," Keisha Russell, a lawyer for the institute. "American business owners should not have to suffer because they want to operate their businesses in accordance with their religious beliefs. Few things are more un-American than government hostility against religion.”

Chick-fil-A said in a statement Tuesday that the company is not involved in the investigation.

"Recent coverage about our company continues to drive an inaccurate narrative about who we are. We are a restaurant company focused on food and hospitality for all, and we have no social or political stance,” the Chick-fil-A statement said. “We are grateful for all our customers and are glad to serve them at any time. We welcome and embrace all people, regardless of religion, race, gender, ethnicity, sexual orientation or gender identity.”